Causality Loop
by lastincurableromantic
Summary: The Doctor, Rose and Jack arrive on an alien planet in the far future, right before the beginning of a riot. Nine/Rose.
1. Chapter 1

**a/n: This was written as a response to a prompt on tumblr from writeworld.**

**disclaimer: Y'all know I don't own Doctor Who. Or Christopher Eccleston. But if he wants to own me, he's welcome to drop me a pm here anytime.**

* * *

**Causality Loop**

**Chapter 1**

"This is incredible," Rose said enthusiastically after walking out of the TARDIS onto the flat roof of a tall building.

"It's a dump," replied the Doctor.

The TARDIS had landed on the top of an alien skyscraper on an alien planet far in the future. At least it was far in the future for Rose. She wasn't certain whether it was the future or the past or the present for the Doctor. As a time traveler, he could have come from any time. To Rose's disappointment, he rarely talked about himself, and he had never shared with her whether the time he was born into was from her relative past or future.

Assuming he had been born at all, and hadn't sprung fully formed from the head of Zeus, she thought, remembering a bit about ancient Greek gods. No, that was Athena, she reminded herself. She could see him as a modern Greek god, strong, powerful, and dead sexy with his steely blue eyes, strong features, broad shoulders and sexy leather jacket. But there was no way in Hades he was, or ever had been, a Greek goddess.

"I think it's interesting," Rose responded. "We haven't been to too many planets. 'S kinda grey, though. And what's that smell?" She wrinkled her nose.

"The usual," he said. "Incompletely consumed fuel resulting in hydrocarbons, oxides of nitrogen, carbon monoxide and ozone. Among other things."

"So, smog."

"Yep, smog," he agreed, nodding with a proud smile for her.

"I used to fly one of those."

Captain Jack Harkness had emerged from the TARDIS behind them and was now gesturing to the aircraft flying low above the buildings. He was wearing his trademark dark trousers, white shirt and braces with his blue greatcoat that looked vaguely military.

"When I was in the Time Agency," he continued. "We flew those all the time. Sucona 15B5. Sweet ride. Interplanetary class, but can fly in the atmosphere as well. Handles beautifully in places like this. It can stop on a dime and handles turns like…"

"I flew one, too," the Doctor interrupted. "Can stall out in conditions like this. Bad furon/hydro conversion design. The later classes, like the 17C class, fixed that problem."

"Well, yeah, but that doesn't negate the beauty of…" Jack's voice trailed off and he and Rose stared at the Doctor. "When did you fly one of those?" he asked.

"Been around a while," the Doctor said absently, staring at their surroundings. "Flown all kinds of things, me. Even raced in the Jacosic thirty million. Came in fifth."

"That's incredible," Jack said, sounding impressed. "Considering the typical number of entries in that race, that is a very nice showing."

"I thought so."

"Doctor," Rose interjected, "where are we?"

"New Japan," he answered. "The planet, not the country. Settled by humans in the year 50,003, after the Sun's solar flares almost decimated the Earth. While it was recovering, most of the population of the Earth moved out to the stars until it was safe to return. Some, like the people who settled out here, stayed. More precisely, we are in the center of New Tokyo, right on the edge of the southeastern quadrant. 16 of May, in the year 51,130."

"Oh, shit," Jack swore.

"Yeah." The Doctor nodded ruefully. "Couldn't 'ave put it better meself."

"Why? What's wrong," Rose asked with just a hint of nervousness creeping into her voice.

"This is the year of the morality riots," Jack told her. "The government here had strict codes in regards to dress and behavior and in the year 51,130 the people began rioting for change. Today in fact. No one ever found out what triggered the riots, though."

"Shall we find out why?" the Doctor asked, raising one eyebrow at Jack. He had a mischievous twinkle in his eye.

"Doctor, what about Rose?" Jack reminded him.

"Oh, yeah," the Doctor said. He sighed loudly as he looked at Rose, his brow furrowed. "Maybe not such a good idea."

Rose rolled her eyes. "I'll be fine. If I could survive Justicia, the Gelth and hanging off a barrage balloon, I think I can survive this."

His eyes narrowed, and he stared at her for a moment thoughtfully.

"Alright," he said finally, "but don't wander off." This last part was accompanied by a shake of his finger at her. He returned to looking at the skyline.

Rose glanced down at herself. She was wearing a new, for her, t-shirt, one she had found in the TARDIS wardrobe. It was bright pink with the slogan "_Someone Went to New Rome and All I Got Was This Lousy Tee Shirt_" emblazoned in dark blue across the chest. She had paired it with her pink hoody, jeans and white trainers.

"If they have a strict dress code, am I alright wearing this?" she asked.

"You're fine," the Doctor answered, not even glancing in her direction.

"You look lovely as always," Jack said with a wink at her.

"Thanks," responded the Doctor. "'S a new jumper. Thought it brought out the color of my eyes."

Rose rolled her eyes again. Every time Jack tried to compliment her, the Doctor jumped in and intercepted it. She didn't protest anymore, though, because she strongly suspected the Doctor was demonstrating a jealous streak. And not of her. And she kinda liked it.

The three of them walked around the TARDIS and found a locked door that led into the building. Pulling out his sonic screwdriver, the Doctor unlocked it and opened the door.

He turned to Rose, automatically taking her hand. His face was covered with a manic grin.

"Let's go and investigate a riot."


	2. Chapter 2

The building was deserted as they descended the short flight of stairs from the roof to the top floor. What's more, it appeared to be still under construction. The walls had been framed out and electrical wiring and plumbing already installed, but the drywall, or its equivalent in the year 50,000, had yet to be put up.

"We're not going to have to walk all the way down, are we?" Jack groaned. "We're what, fifty stories up?"

"Nah," replied the Doctor. "With this many stories, there'll already be an elevator."

"But there's no guarantee it'll be working when the building's empty."

"Sure there is." The Doctor grinned, holding out his sonic screwdriver. "Dead useful, this is. Much more than a sonic blaster."

"Depends on the situation," Jack countered. "Didn't help much in 1941."

It was an old argument and although it was good natured, Rose wanted to stay out of it. Besides, she wasn't entirely sure what side she'd be on. They both had their points. And Jack was right. The blaster had been much more useful in saving their lives in 1941, but she really didn't want to side with Jack against the Doctor. And not just over the usefulness of the sonic.

_Stop it_, she told herself firmly. The Doctor was her best friend. But her thoughts about him had become quite interesting ever since talking about dancing with him in Albion Hospital in 1941. More like fantasies, really, now that she realized he wasn't quite as asexual as she had originally thought.

Who was she kidding? She had had fantasies about him since _before_ he had invited her to travel with him in the TARDIS. And deep down she had always known he wasn't as asexual as he acted around her. She had just thought he wasn't interested in her that way, guessing his feelings towards her were more fatherly than anything else.

But now she wasn't sure about that. Between his minor jealousies and the way he looked at her when he thought she wasn't looking, she was beginning to wonder if there wasn't more to it. Plus, there were his comments about showing her his moves and then him dancing with her in the TARDIS. Although it was only literal dancing, not metaphorical. And she was more than slightly disappointed about that.

By this time they had found the elevator, and, with more than a little help from the Doctor's sonic, they had quickly made it to the ground floor and out to the street. The air smelled cleaner there, Rose noticed in relief, but the city just looked like a city. From where they stood, with the neon signs and the pavement and the stoplights, they could have even been in the 21st century. That is, if you didn't look at the flying cars.

"Seems pretty quiet," Jack said. "Do you know where the riots actually started?"

The Doctor shook his head. "Just this general area. Somewhere within a six block radius from here, I think. Not sure though."

"We should split up, cover more area that way," Jack suggested.

The Doctor shrugged. "'S alright with me. You have any objections, Rose?"

"Not me," she said.

"Well then, I'll head this way," Jack pointed up the street, "and you two head that way."

Jack walked off in the direction he had indicated, but not without glancing at the people, and aliens, around him with more than casual interest.

"He'll never change," Rose said.

"Would you want him to?" the Doctor asked.

"Nah," she said. "Cos then he wouldn't be Jack. And the universe would be a much poorer place without Captain Jack."

The Doctor looked at her suspiciously.

"Don't cha think?" she prompted mischievously.

"Let's get goin'," he said, not answering, and he tightened his grip on her hand possessively. She grinned.

"So, why were you so quick to let Jack head off on his own?" Rose asked.

"Do ya really think I coulda stopped him?"

"Well, no," she admitted. "But you didn't even protest."

"No, I didn't," he said.

"Why?"

"You really wanna know?"

"Wouldn't 'a asked if I didn't," she told him.

"Causality loop," he said.

"What?"

"Causality loop." He looked at her with one eyebrow raised. "The riot was in response to restrictive laws regarding behavior and dress codes. Who do you know who could inspire a riot against behavior and dress codes just by his mere presence."

Rose's eyes widened.

"But, but, wouldn't that bring the reapers or something?"

"Not if he was the one who started the riots in the first place. And if he did, the_ last_ place I wanna be is with him."

"Shouldn't we try to stop him?" she asked.

"Nope. The riots happened. They are history. In fact, after the riots, the government becomes much less restrictive across the board not only in regards to personal behavior, but also in trade, tourism, immigration… ushers in a golden age on this planet that lasts a thousand years. And I don't know that Jack causes them, jus' seems likely, especially because the TARDIS herself landed us here. I was aimin' for Selious 4."

"So the TARDIS brought us here, and Jack's investigating the riots, riots he might have caused himself?" Rose asked.

"Welcome to time travel."

* * *

Jack wandered around the neighborhood for a while, looking for any possible signs of a trigger for a riot. There was nothing. Absolutely nothing. There _were_ quite a few women, and not a few men, who gave him long, lingering looks, looks he returned with a wink, but although any one of a number of them would have been interesting to get to know, he wasn't stupid enough to try and pick up someone on the street. Not on this planet. And despite the excuse of trying to investigate the cause of the coming riot, he was really just trying to give the Doctor and Rose a little time alone. The sexual tension between them was so thick you could cut it with a knife, and since they weren't doing anything to relieve it, it was tough to be around them sometimes. He didn't know how they could stand it.

It had occurred to him more than once that maybe the reason they weren't doing anything to relieve the tension between them was because he was around all the time. And he really didn't want to be a third wheel. A third participant maybe, but not a third wheel.

With those thoughts in his mind, he realized he_ really_ needed to blow off a little steam. But not yet. If he wasn't careful, he could end up starting the riot himself. Maybe later, he thought. After the riot. Or maybe during. He wasn't picky.

* * *

As they walked down the street hand in hand, Rose noticed a number of people looking at them curiously, but she assumed it was due to the type of clothing they were wearing. Most people, men and women, were dressed fairly formally in suits that would have been suitable for business, but a number of them wore traditional kimonos, which surprised Rose given how far in the future they were. She reminded herself she shouldn't be surprised by anything while traveling with the Doctor. There were, however, a sizable minority of people who were dressed as they were, in jeans, so she wasn't quite sure why they were being stared at.

She turned to the Doctor to ask about it but then noticed that the scent of cooking food had replaced the earlier odor of pollution. Rose's stomach grumbled.

"Hungry, are ya?" the Doctor asked.

"I could eat," she said.

"So could I," he admitted. "Got to warn you, though, there's no chips in New Tokyo. Think you'll live?"

"Dunno. Let's find out," she said, grinning at him.

Letting go of his hand, they linked arms and headed to the nearest restaurant.


	3. Chapter 3

**Chapter Three**

After an hour of sitting at a bar just down the street from where he had separated from the Doctor and Rose, Jack Harkness was getting bored. He had had three sakes, and although they were stronger than he remembered, they were far less than he would have to drink to get drunk.

He had also flirted with four people, first the bartender and then a different person with each sake he had had. The bartender was of a species he didn't recognize, green with cactus like needles covering his body, but the bartender seemed receptive and the needles just made the challenge more interesting in Jack's opinion.

Just has he had ordered another drink, a beautiful young woman in a red silk kimono sat down next to him, her long black hair swept up into an ancient style and held in place with chop sticks. Jack glanced at her, and she smiled shyly at him.

He turned to face her and leaned on the edge of the bar.

"Hi, I'm Jack Harkness," he said, flashing her a wide grin. "Can I buy you a drink? By the way, I love your kimono…"

* * *

The Doctor and Rose sat on pillows at a low table, eating what passed for traditional Japanese fare in New Tokyo.

"Now this looks like rice," he said, pointing at the contents of a bowl with traditional chopsticks, "but it's not the kind of rice you'd ever have gotten on your planet. It's actually closer to triticale, which is a hybrid of wheat and rye. And the sashimi comes from an aquatic creature native to this planet."

Rose used her chopsticks to lift a piece of the sashimi to her mouth.

"Not bad," Rose said, nodding after she had tasted it.

The Doctor was proud of her. So many of his previous companions would have turned up their noses at unfamiliar foods, but not Rose. She was always up for anything he suggested, whether it was exploring a new planet, trying new foods, or investigating trouble. Clever, compassionate and completely fantastic, that was his Rose.

Oops. Where did that thought come from? She was his best friend, but she wasn't _his_. Not like that. And why was he thinking of her that way? That was a line he did not cross. Nope, no way, no how, no matter how beautiful she was. Especially with her hair like that, hanging down around her shoulders….

Oops again. He picked up his drink and took a sip to break his train of thought.

As they were having a traditional Japanese meal, he had ordered sake, but for some reason he hadn't noticed how strong it was until now.

Rose was lifting her tiny cup to her lips. "This is really good," she said after taking a sip.

"Best be careful with that," he said to her. "'S stronger than I realized."

She rolled her eyes. "I'm fine," she said. "Haven't had that much. I used to drink more on a typical night out with Shareen."

"If you say so," he said, lifting one eyebrow.

* * *

Jack glanced at the clock behind the bar. 17:00. The riot had to be starting soon. And as much as the Doctor had said he wanted to find out what caused it, neither one of them wanted Rose to get caught in the middle of it. Lifting his cup to his mouth, he finished his drink before heading out to the street to find them.

The Doctor paid the bill, and they headed out to the street. Rose seemed a bit unsteady on her feet so he wrapped an arm around her, not noticing the stares the two of them were receiving.

"Let's get you back to the TARDIS," he said to her. "You seem to be having trouble walkin'."

"'S just because my leg fell asleep while we were sitting on the floor," she told him. She shook it a little to try to get the circulation back in it. From the look he was giving her, she could tell he didn't believe her.

"If you say so," he said.

"I do say so. Besides, what about investigating the riot?" she asked.

"We'll let Jack do that," he told her as he walked her down the street.

Rose snorted. "Hard to investigate a riot when you're busy causing it."

He looked down at her, laughing, and with a grin she looked up at him, meeting his eyes. It faded as she stared at him thoughtfully. He had been kidding earlier, but his jumper really did bring out the color of his eyes.

"Y'know, Doctor, you have the most beautiful eyes," she told him.

He raised his eyebrows at her comment. "That's the sake talkin'."

"Nope," she answered. "I've always thought that. They are the most incredible shade of blue. And I like your voice, too."

"Even if I sound like I'm from the North?" he asked in amusement.

She stopped walking, forcing him to stop as well. Pulling away from him, she turned to face him directly. "Even though you sound like you're from the North." Her eyes drifted to his mouth. "And you have the most beautiful lips."

"Rose," he said warningly.

"You do, you know. In fact, you're absolutely gorgeous, and the best part is you're not a bit conceited. In fact, you don't even realize it."

"Now I know you're drunk, _and_ we need to get your eyes checked on top of it."

Rose shook her head. "I'm not drunk. And my eyes are fine. You shouldn't put yourself down like that. I think you are… absolutely fantastic."

He stared at her. They were in dangerous territory, territory they had been dancing around ever since they had danced in the TARDIS console room. And now that she had brought it out in the open between them, he wasn't exactly sure what to do about it. Oh, he knew what he _should_ do….

She took a step closer to him.

"Rose," he said. This time it came out as a plea, but he wasn't sure if it was for her to stop or to continue.

"I want you to remember something," she said. "I am not drunk. I am doing something I've wanted to do for a long time; the sake just made me brave enough to do it." She stared into his eyes as she took another step closer to him. Grabbing the lapels of his leather jacket to steady herself, she stood on her tiptoes and kissed him lightly on the lips.

"Rose Tyler," he said, staring at her as if she were a puzzle he couldn't quite figure out. He took a deep breath and let it out in a rush. "Oh, hell," he said. Pulling her into his arms, he bent his head to hers and kissed her, unaware a crowd was gathering around them.

From the other end of the street, Jack saw the crowd gathering.

"Looks like it's starting," he said to himself. "Wonder what's causing it." Knowing that that was the direction the Doctor and Rose had headed, he took off at a jog to try and find them.

As he neared the crowd, he started calling them.

"Doctor, Rose," he yelled.

At the sound of Jack calling their names they broke apart. The Doctor and Rose stared around them in amazement. While they had been kissing, they had become surrounded by people. A number of people in the crowd started to applaud and others were taking pictures of them.

"Doctor!"

"Jack, we're over here," the Doctor called back.

Jack pushed his way through to the center of the crowd to find that Rose was in the Doctor's arms. He grinned.

"I'm not even gonna ask," he said, chuckling. "But I think we need to get going." He pointed to a camera on the corner of a building that was aimed in their direction. "CCTV."

The Doctor groaned. "That means the authorities are gonna be here any minute now."

"What?" Rose asked. "What's goin' on? And why are all those people takin' pictures of us?"

"Remember when we were talking about the government having very strict codes of conduct?" Jack asked. Rose nodded. "Well, that means no public displays of affection. If we don't get out of here right now, the two of you are going to get arrested." He laughed.

"What!" Rose cried in astonishment and then began to giggle.

"C'mon," the Doctor said gruffly. He grabbed Rose's hand and pulled her through the crowd, some of whom had begun to display their own affection for each other.

The crowd had grown so large that the way to the building where the TARDIS was located was entirely blocked, and the sounds of police sirens could be heard in the distance. The Doctor swore under his breath.

"We've got to get outa here," he said.

"Doctor, we've lost Jack," she told him.

"Jack can take care of himself. Besides, they're not lookin' for him, they're lookin' for us." He looked around for a way to escape. "Okay, I think I spotted somethin'," he said, and started pushing through the crowd again. He pulled her into a narrow alleyway.

"I don't think anyone noticed us comin' in here," he told her. "We should be safe for the moment. Too bad this alley's blocked off at the other end. That means we're gonna have to wait for the crowds to die down before we get outa here." He leaned against the side of the building and looked at her. "What?"

"Y'know what this means, doncha?" she asked, trying not to laugh. "It means that Jack didn't cause the riot at all. We did."

The Doctor chuckled. "That we did," he said, grinning. "And as long as they already want to arrest us…." He jerked his head at her. "C'mere."

He pulled her into his arms and kissed her again, slowly and deeply.

"Well, look at the two of you," Jack said from the entrance to the alley, and they broke apart, the Doctor looking mildly sheepish, Rose with a pleased as punch look on her face. Jack shook his head, trying desperately not to laugh. "Doctor, you finally decide to snog her and you pick the most repressed planet in the quadrant to do it _and_ manage to start a riot in the process to boot. I'm so proud of you."

The Doctor rolled his eyes and Rose started laughing.

"You forgot where you were, didn't you?" Jack asked, raising his eyebrows and smirking. The Doctor's mouth twisted in an effort not to grin.

"How does it look out there?" the Doctor asked him, not answering the question.

"Seems the reports of a riot were a bit exaggerated. Feels more like a block party." Jack laughed. "The street is jam packed with people. Someone started piping music into the street from somewhere and a whole bunch of people started dancing. One of the local restaurants is even selling food out there. The cops are out there looking for you two, though."

"I've gotta get Rose outa here and back to the TARDIS," the Doctor told him. "I really don't wanna have her get arrested again. We're gonna need you to create a diversion."

"Well, all right," Jack said. "But you're gonna have to carry them back to the TARDIS."

"Carry what back?" the Doctor asked. Jack threw his coat at him, hitting him in the chest. Jack then toed off his boots, pulled his braces off over his shoulders and started unbuttoning his shirt.

"What are you doin'?" the Doctor demanded.

"You said to create a diversion," he replied with a cheeky grin.

Rose laughed as Jack tossed the Doctor his shirt and vest. As he started to unbutton his trousers, she vaguely wondered what type of pants he wore under them.

Oh.

The answer was none.

"I'll meet you back at the TARDIS," he told them. "But if I'm not back by morning, you may need to bail me out of jail." He tossed his trousers to the Doctor, who neatly caught them. "No rush. I figure the two of you could use a little time alone. Besides, one of the cops out there is kinda cute." He crossed back to the entrance to the alley. "Rose, be gentle with him." He winked at her, and she grinned back. "Have fun, you two."

After he ran out of the alley, the sounds of shrieks, laughter, applause, catcalls and wolf whistles filtered in from the street.

Rose turned to the Doctor as he wrapped Jack's clothes and boots into a tidy bundle.

"Y'know," she said, "I never used to believe half the stories he told. Now I think I do."

"The diversion he created isn't gonna distract 'em for long," the Doctor said, putting the bundle of Jack's clothes under his left arm. "We've gotta take advantage of it while we can." He took her left hand in his right and gave her a manic grin.

"Run!"


End file.
